“Lead is unfortunately in school water throughout the nation," Dr. Hanna-Attisha said. “Schools are meant to be places were children learn and develop, not places where you can potentially be exposed to a neurotoxin which impedes learning and development.”

San Diego Unified began targeted testing for lead in school drinking water in 2017, working with its water provider, the City of San Diego, to assess the extent of the problem. Tests found elevated levels of lead in about 20 percent of schools tested. Outlets with elevated levels of lead were turned off, so students could not drink from them until they were repaired or replaced. The district also made plans to expand testing to include every outlet at every school.